Preparation, Catalytic Properties And Thermokinetics Of Ferrite Micro/Nanomaterials

Ferrite nanomaterials with spinel structure have attracted much interest owing toits excellent electric, magnetic properties and their promising technologicalapplications. As we all know, the intrinsic properties and applications of the ferritenanomaterials are mainly determined by its sizes, morphologies and chemicalcompositions. Therefore, it is important to controlled synthesis of typical ferritenanostructures and understand the correlations between the material properties and itsnanostructures. In this paper, several representative ferriferrous oxide nanoparticlesand ferriferrous oxide/zinc oxide composites have been successfully fabricated vialiquid phase method. The influence of both their sizes and shapes on the magnetic andphotocatalytic properties has been studied. The thermodynamics and kinetic of in situphotocatalysis was investigated by calorimetry technique.Herein, we developed a novel microemulsion-assisted solvothermal route for thesynthesis of grass-like, petal-like, flower-like and spindle-like Fe3O4nanocrysals inone-pot. The formation mechanisms for Fe3O4nanocrysals have been investigated indetails. The effect of its sizes and morphologies on the magnetic and photocatalyticproperties has been explored.A simple and environmental hydrothermal method was presented for thepreparation of Fe3O4/ZnO composites. Well-defined spindle-like and poroushexagonal cake-like Fe3O4/ZnO micro/nanocomposites were successfully synthesizedin one-step by this route, using FeCl3as the iron source, ethylene glycol as the solventand reducing agent,[Zn(OH)4]2-as the zinc source and alkaline solution. The sizes andshapes of Fe3O4/ZnO crystals can be readily tuned by adjusting experimentalconditions. The photocatalytic properties of the Fe3O4/ZnO micro/nanocompositeswere also investigated, the results revealed that the photocatalytic activity was so highthat the methylene blue solution could be degradated quickly and thoroughly. Inaddition, the more defects in the crystals and the smaller particle sizes are, the betterthe catalytic performance is, owing to the photocatalytic performance withmorphology effect and size effect.The thermodynamics and kinetics of the degradation of methylene blue wereanalyzed for the first time by employing a novel photoreaction-microcalorimetricsystem which designed by ourselves. The in situ microcalorimetric heat flow curveand in situ thermodynamics and kinetics information from the photocatalytic process were monitored using microcalorimetry. Combined with the dynamic informationobtained from UV-Vis spectra, the photocatalytic degradation mechanism werediscussed deeply.